So the agency can size/place content: returns the canvas size + zone positions/sizes for the
layouts its designated playlists feed, marking which zones are theirs. DEVICE-FREE BY
CONSTRUCTION - the query path is playlist_items.zone_id -> layout_zones -> layouts and never
touches devices/groups/schedules, so device names/locations/IPs/topology are structurally
absent, not filtered. Geometry only - no sibling-zone content. layout.name included (admin's
canvas name); thumbnail_data omitted (could render other zones' content).
Confinement query in lib/agency-layouts.js, bite-tested: own layout YES, a non-designated
playlist's layout NO, response has NO device fields (asserted on a db where a location-named
device exists), and neutralizing the t.token_id filter goes red. 142 suite green.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
